1. Field of the Invention
This invention relates to a method and apparatus for cutting a continuously moving sheet material into sheets of desired length by a jet stream of fluid under very high pressure.
2. Description of the Prior Art
A continuous cutting apparatus is commonly known which is capable of continuously cutting a continuously fed sheet material such as a corrugated cardboard material into sheets of predetermined length in sequence. A rotary shear utilizing the sheet cutting engagement of cutter blades mounted to cutter rolls is widely employed as such a continuous cutting apparatus. However, with the recent tendency toward the increase in both the thickness and the width of sheet materials of the kind above described, the cutter rolls tend to be bent during sheet cutting operation, and the power required for the sheet cutting is increased due to the increase in the weight of the moving parts, resulting in difficulty of operation control including velocity control. Because of the difficulty of the velocity and other control, successful application of the conventional rotary shear to the cutting of the sheet material becomes gradually difficult.
A novel cutting technique has been developed recently according to which a fluid obtained by mixing a polymer in water is jetted from a nozzle at a pressure of about 1,500 to 7,000 kg/cm.sup.2 for cutting stones and lumber utilizing the energy of the jet stream of fluid under very high pressure. Noting the fact that this jet stream of fluid under very high pressure has very great energy and application of this cutting technique to the cutting of a corrugated cardboard sheet material provides a very beautiful appearance at the cut section, the present invention contemplates an application of this cutting technique to the continuous cutting of a moving sheet material having a large thickness and a large width which is difficult to cut with the conventional rotary shear although not impossible.